<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2013-04-02</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001175108</issuerCik>
        <issuerName>ROTECH HEALTHCARE INC</issuerName>
        <issuerTradingSymbol>ROHI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001251565</rptOwnerCik>
            <rptOwnerName>WYNNEFIELD PARTNERS SMALL CAP VALUE LP I</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>450 SEVENTH AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 509</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10123</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000899083</rptOwnerCik>
            <rptOwnerName>WYNNEFIELD PARTNERS SMALL CAP VALUE LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>450 SEVENTH AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 509</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10123</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001030806</rptOwnerCik>
            <rptOwnerName>WYNNEFIELD SMALL CAP VALUE OFFSHORE FUND LTD</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>450 SEVENTH AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 509</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10123</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001056835</rptOwnerCik>
            <rptOwnerName>WYNNEFIELD CAPITAL MANAGEMENT LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>450 SEVENTH AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 509</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10123</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001251567</rptOwnerCik>
            <rptOwnerName>WYNNEFIELD CAPITAL INC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>450 SEVENTH AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 509</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10123</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001289453</rptOwnerCik>
            <rptOwnerName>Wynnefield Capital, Inc. Profit Sharing Plan</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>450 SEVENTH AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 509</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10123</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001017043</rptOwnerCik>
            <rptOwnerName>OBUS NELSON</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>450 SEVENTH AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 509</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10123</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001251568</rptOwnerCik>
            <rptOwnerName>LANDES JOSHUA</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>450 SEVENTH AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 509</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10123</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.0001 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2013-04-02</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4750</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.12</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1791346</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F1"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.0001 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2013-04-02</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>5250</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.12</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2028425</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnotes</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The Reporting Person directly beneficially owns 1,791,346 shares of common stock, $0.0001 par value per share (&quot;Common Stock&quot;) of Rotech Healthcare Inc. (the &quot;Issuer&quot;). Wynnefield Capital Management, LLC, as the sole general partner of the Reporting Person, has an indirect beneficial ownership interest in the shares of Common Stock that the Reporting Person directly beneficially owns. Nelson Obus and Joshua Landes, as co-managing members of Wynnefield Capital Management, LLC, have an indirect beneficial ownership interest in the shares of Common Stock that the Reporting Person directly beneficially owns.</footnote>
        <footnote id="F2">The Reporting Person has an indirect beneficial ownership interest in 1,139,621 shares of Common Stock, which are directly beneficially owned by Wynnefield Partners Small Cap Value, L.P., as members of a group under Section 13(d) of the Securities Exchange Act of 1934, as amended (the &quot;Exchange Act&quot;). Wynnefield Partners Small Cap Value, L.P., which maintains offices at the same address as the Reporting Person, is filing this statement jointly with the Reporting Person. Wynnefield Capital Management, LLC, as the sole general partner of Wynnefield Partners Small Cap Value, L.P., has an indirect beneficial ownership interest in the shares of Common Stock that Wynnefield Partners Small Cap Value L.P. directly beneficially owns. Nelson Obus and Joshua Landes, as co-managing members of Wynnefield Capital Management, LLC, have an indirect beneficial ownership interest in the shares of Common Stock that Wynnefield Partners Small Cap Value, L.P. directly beneficially owns.</footnote>
        <footnote id="F3">The Reporting Person has an indirect beneficial ownership interest in 863,804 shares of Common Stock, which are directly beneficially owned by Wynnefield Small Cap Value Offshore Fund, Ltd., as members of a group under Section 13(d) of the Exchange Act. Wynnefield Small Cap Value Offshore Fund, Ltd., which maintains offices at the same address as the Reporting Person, is filing this statement jointly with the Reporting Person. Wynnefield Capital, Inc. as the sole investment manager of Wynnefield Small Cap Value Offshore Fund, Ltd., has an indirect beneficial ownership interest in the shares of Common Stock that Wynnefield Small Cap Value Offshore Fund, Ltd. directly beneficially owns. Nelson Obus and Joshua Landes, as principal executive officers of Wynnefield Capital, Inc., have an indirect beneficial ownership interest in the shares of Common Stock that Wynnefield Small Cap Value Offshore Fund, Ltd. directly beneficially owns.</footnote>
        <footnote id="F4">The Reporting Person has an indirect beneficial ownership interest in 25,000 shares of Common Stock, which are directly beneficially owned by Wynnefield Capital, Inc. Profit Sharing Plan, as members of a group under Section 13 (d) of the Exchange Act. Wynnefield Capital, Inc. Profit Sharing Plan, which maintains offices at the same address as the Reporting Person, is filing this statement jointly with the Reporting Person. Nelson Obus, as the portfolio manager of Wynnefield Capital, Inc. Profit Sharing Plan, has an indirect beneficial ownership interest in the shares of Common Stock that Wynnefield Capital, Inc. Profit Sharing Plan directly beneficially owns.</footnote>
    </footnotes>

    <remarks>Each of the Reporting Owners identified in this statement disclaims beneficial ownership of the securities described in this statement, except to the extent of their individual respective pecuniary interest in such securities. The filing of this statement shall not be deemed an admission that any of the Reporting Owners identified in this statement are, for purposes of Section 16 of the Exchange Act or otherwise, the beneficial owner of any securities specified in this statement other than those directly beneficially owned by them.</remarks>

    <ownerSignature>
        <signatureName>WYNNEFIELD PARTNERS SMALL CAP VALUE, L.P. I, By: Wynnefield Capital Management, LLC, General Partner, By: /s/ Nelson Obus, Managing Member</signatureName>
        <signatureDate>2013-04-04</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>WYNNEFIELD PARTNERS SMALL CAP VALUE, L.P., By: Wynnefield Capital Management, LLC, General Partner, By: /s/ Nelson Obus, Managing Member</signatureName>
        <signatureDate>2013-04-04</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>WYNNEFIELD SMALL CAP VALUE OFFSHORE FUND, LTD., By: Wynnefield Capital, Inc., By: /s/ Nelson Obus, President</signatureName>
        <signatureDate>2013-04-04</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>WYNNEFIELD CAPITAL MANAGEMENT, LLC, By: /s/ Nelson Obus, Managing Member</signatureName>
        <signatureDate>2013-04-04</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>WYNNEFIELD CAPITAL, INC., By: /s/ Nelson Obus, President</signatureName>
        <signatureDate>2013-04-04</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>WYNNEFIELD CAPITAL INC. PROFIT SHARING PLAN, By: /s/ Nelson Obus, General Partner</signatureName>
        <signatureDate>2013-04-04</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Nelson Obus, individually</signatureName>
        <signatureDate>2013-04-04</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Joshua Landes, individually</signatureName>
        <signatureDate>2013-04-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
